Infection with H. pylori- is responsible for major morbidity and mortality throughout the world. The current market for H. pylori antibiotics is estimated to be between l to 2 billion dollars annually and there is clear emergence of H. pylori strains that are resistant to these treatments. For these reasons, the development of a safe and effective vaccine against H. pylori is of both great medical importance and commercial value. The specific aim of this research is to understand the immunological response that is responsible for the observation that a minority of rhesus monkeys appear to be resistant to chronic infection by H. pylori. These studies will evaluate the hypothesis that the resistant monkeys have a distinct difference in the specificity of their immune response upon challenge with H. pylori. Plasma and gastric juice samples will be collected from both resistant and non-resistant monkeys following a challenge with H. pylori and evaluated for the specificity of their anti-H. pylori IgG and IgA responses. Phase II studies will involve further characterization of the antigens identified in Phase I and evaluation of their utility for inducing a protective immune response in nonhuman primates. PROPISED COMMERCIAL APPLICATIONS: Infection with H. pylori has been associated with morbidity and mortality on all five continents. The current market for H. pylori-i antibiotics is estimated to be between l to 2 billion dollars annually and there is clear emergence of H. pylori strains that are resistant to these treatments. For these reasons, the development of a safe and effective vaccine against H. pylori is of both great medical importance and commercial value.